To provide an image forming device configured to reliably determine whether a toner bottle is new one or not and further to reduce the amount of toner remaining in the toner bottle as much as possible when toner empty is determined.

A image forming device supplies toner from a toner bottle 7 housing toner to a buffer part 16, and develops an electrostatic image with the toner supplied from the buffer part to form an image. The image forming device includes: toner detection means 18 for detecting whether there is toner in the buffer part; and toner supply means having a plurality of supply modes different in toner supply efficiency. The toner supply means supplies toner from the toner bottle to the buffer part in a first supply mode when the toner detection means detects toner empty during image forming operation, and supplies the toner in a second supply mode having larger rotation amount per unit time than the first supply mode when a determination is made as to whether a new toner bottle has been set.